1. Technical Field
The present invention relates generally to a method for cross-section processing and observation, and apparatus therefore, the method forming a particular region including a particular observation target object of a sample by using a focused ion beam, irradiating the particular region by using an electron beam to obtain a cross-section image, and obtaining a three-dimensional image of the particular observation target object.
2. Description of the Related Art
For example, as a method of interpreting or observing an internal structure of a sample such as a semiconductor device, etc. or performing a three-dimensional observation thereof, a method of cross-section processing and observation (for example, Patent Document 1) is well known. The method includes: by using a composite charged particle beam device having a focused ion beam (FIB) column and an electron beam (EB) column, repeating both cross-section processing using a focused ion beam (FIB) and scanning electron microscopy (SEM) observation using an electron beam (EB) irradiating a cross section so as to obtain multiple cross-section images of a target sample, and obtaining a three-dimensional image of the sample by overlaying the multiple cross-section images thereafter.
The method of cross-section processing and observation is a method called “Cut&See” in which cross-section processing using a FIB is referred to as “Cut” and cross-section observation using an EB is referred to as “See”, Cut and See are repeated to obtain a three-dimensional image. In the method, by using the obtained three-dimensional image, it is possible to view a three-dimensional shape of a target sample in various directions. In addition, it is possible to reproduce an arbitrary cross-section image of a target sample, something impossible using other methods.
As a specific example, etching processing is performed by irradiating a sample with an FIB to expose a cross section of the sample. Next, SEM observation is performed on the exposed cross section to obtain a cross-section image. Etching processing is performed again to expose a subsequent cross section. Next, SEM observation is performed again to obtain a second cross-section image. As described above, multiple cross-section images are obtained by repeating the etching processing and the SEM observation along an arbitrary direction of the sample. Lastly, the obtained multiple cross-section images are overlaid, whereby a three-dimensional image through which the inside of the sample can be seen is obtained.